The present invention relates to an exercise machine, such as bicycle ergometer, treadmill and rowing ergometer, a physical strength evaluation method and a pulse rate meter.
Method and apparatus for determining exertion levels interested in this invention are disclosed, for example, in International Publication No. WO96/20640. According to the disclosure, heartbeat of a person engaged in training is monitored. From an electrocardiographic signal obtained, a QRS complex waveform, for example, is measured to calculate the heartbeat rate. Based on a power of a spectrum derived from the heartbeat rate, an exertion level of the exercising person is determined.
Further, conventional method and apparatus for measuring muscular endurance of a person engaged in exercise are disclosed, for example, in Japanese Patent Publication No. 7-38885. According to the disclosure, a load of an exercising person is calculated from the product of a heartbeat rate and a blood pressure under vasoconstriction, and from the result, the muscular endurance is calculated.
The load of a person engaged in training or exercise has conventionally been measured as described above. Such measurement has also made it possible to estimate the load of an exercising person.
Conventionally, exercise machines such as a bicycle ergometer and others have been commercially available for health maintenance and enhancement. In some of such exercise machines, a person inputs his/her age, sex and the like, and an exercise program is arranged according to such information based on statistically predetermined exertion intensity. For evaluation of a physical strength level, some machines have adapted a method of estimating the maximum oxygen intake based on a change of pulsation or the like corresponding to a change of exertion load.
There is a factor for decision of safe and effective exercise; i.e., an anaerobic threshold (hereinafter, also referred to as xe2x80x9cATxe2x80x9d). This threshold value of exertion intensity shows a maximum exertion level at which exercise can be done without an abrupt increase of lactic acid in the blood. The AT is conventionally determined employing an invasive method by taking a blood sample to examine the lactic acid level, or in a restraining manner by measuring changes of oxygen and carbondioxide partial pressures in exhalation by breathing gas analysis.
Further, for evaluation of physical strength, there are conventionally known methods of estimating maximum oxygen intake, maximum exertion intensity, maximum heartbeat rate and others based on a change of pulsation or the like with respect to the exertion load.
Such conventional exercise machines and apparatuses for determining exertion levels, however, have posed the following problems:
{circle around (1)} The data obtained from the apparatus and method for determining the exertion level has been used only physiologically to determine the exertion level in training or exercise; the data has not been utilized effectively.
{circle around (2)} Setting of exertion intensity does not conform to working capacity of each person; a sought-after effect cannot be obtained sufficiently from the exercise.
{circle around (3)} Although the AT is considered most appropriate as the exertion intensity in conformity with the working capacity of the individual, measurement of the AT is restraining and requires a special apparatus such as a breathing gas analyzer; such a measuring apparatus cannot practically be mounted on an exercise machine.
{circle around (4)} The AT, which represents aerobic working capacity important for decision of physical strength, cannot be determined by or displayed on the exercise machine due to the reason stated in {circle around (3)} above.
The present invention is directed to solve the above-described problems, and its object is to provide an exercise machine which allows an exertion level to be readily and accurately found so that the value can be used for effective training.
Another object of the present invention is to provide an exercise machine which allows an anaerobic threshold to be readily and accurately found so that the value can be used for effective training.
Yet another object of the present invention is to provide an exercise machine and a physical strength evaluating method which allow physical strength and exertion levels to be readily found at the same time, allow a user to understand his/her own working capacity in more detail to do appropriate exercise, and allow the physical strength and exertion levels to be evaluated with high precision in a time period as short as possible.
A still further object of the present invention is to provide a pulse rate meter which allows an exertion level to be readily and accurately found.
The exercise machine according to the present invention includes: a load device capable of changing a load; a physiological signal measuring unit measuring a physiological signal noninvasively over time; an exertion level estimating unit estimating an exertion level based on the physiological signal corresponding to the change of the load of the load device; and a unit for controlling the load of the load device employing the exertion level estimated.
The exertion level is estimated based on the physiological signal corresponding to the change of the load of the load device, and the load of the load device is controlled to come close to the estimated exertion level. Therefore, an exercise machine allowing a user to do appropriate exercise corresponding to his/her own working capacity can be provided.
Preferably, the exertion level estimating unit estimates the exertion level based on a change of the physiological signal in response to the change of the load of the load device.
More preferably, the exertion level estimating unit estimates an anaerobic threshold as the exertion level.
The exertion level estimating unit estimates the anaerobic threshold as the exertion level, and the load of the exercise machine is controlled based on this threshold value. Thus, an exercise machine allowing a user to do appropriate exercise more efficiently corresponding to his/her own working capacity can be provided.
According to an aspect of the present invention, the exertion level estimating unit includes a unit for calculating a fluctuation of heartbeat power rate intervals in each electrocardiographic signal detected, a unit for calculating a power of the fluctuation of heartbeat rate intervals and a unit for finding a convergence point of a change of the power with respect to the increase of the load, and estimates an exertion load corresponding to the convergence point as the exertion level.
The fluctuation of heartbeat rate intervals in the electrocardiographic signal is calculated and the convergence point of the power change of the fluctuation with respect to the load increase is obtained to estimate the exertion level. Thus, an exercise machine capable of evaluating the exertion level with high precision in a short time period can be provided.
According to another aspect of the present invention, the exercise machine includes: a load device gradually increasing a load over time; an electrocardiographic sensor detecting an electrocardiographic signal; a unit for measuring a heartbeat rate of the electrocardiographic signal detected while the load is gradually increased; a unit for calculating a fluctuation of heartbeat rate intervals in the electrocardiographic signal; an exertion level estimating unit estimating an exertion level based on the heartbeat rate and the fluctuation of heartbeat rate intervals; a unit for estimating physical strength based on a slope of the change of the heartbeat rate with respect to the change of the load around the exertion level estimated by the exertion level estimating unit; and a unit for controlling the load device to make the load come close to the level corresponding to the estimated physical strength.
The heartbeat rate of the electrocardiographic signal detected while gradually increasing the load is measured, a fluctuation of which is calculated, and the exertion level is estimated based on the heartbeat rate and the fluctuation of heartbeat rate intervals. The load of the load device is controlled to come around the estimated exertion level. Therefore, an exercise machine allowing a user to understand his/her own working capacity more precisely and hence to do appropriate exercise can be provided.
According to a still further aspect of the present invention, the physical strength evaluating method includes the steps of: gradually increasing a load of a load device; detecting by an electrocardiographic sensor an electrocardiographic signal under an increasing exertion load while the load is gradually increased; finding a heartbeat rate and a fluctuation of heartbeat rate intervals from the electrocardiographic signal detected; and estimating physical strength and an exertion level at the same time from the heartbeat rate and the fluctuation of heartbeat rate intervals thus obtained.
The electrocardiographic sensor detects the electrocardiographic signal corresponding to the increasing exertion load, and the heartbeat rate and the fluctuation of heartbeat rate intervals are obtained from the detected electrocardiographic signal. Based on thus obtained heartbeat rate and fluctuation of heartbeat rate intervals, the physical strength and the exertion level are estimated at the same time. Thus, a physical strength evaluating method capable of evaluating the physical strength and the exertion level with high precision in a short time period can be provided.
According to yet another aspect of the present invention, the pulse rate meter includes: a pulse rate sensor detecting a pulse rate signal produced by a heart; an alarm unit demanding a gradual increase of a pitch of exercise; an exertion level estimating unit estimating an exertion level based on the pulse rate signal detected by the pulse rate sensor while exercise is gradually intensified; and a unit for setting a pace based on the pitch of exercise corresponding to the exertion level estimated.
As the pulse rate meter can estimate the exertion level from the pulse rate signal detected while the pitch of exercise is gradually increased, it is possible to readily find an exertion level of an individual while he/she is engaged in exercise in the field.